Relationships Between Salts and Acidity In Batteries



The battery made in class consisted of 2 different metals with salt water. The salt conducts electricity, while the two different metals. There are several different ways to make a battery. First is a series setup, with aluminum connected to copper which is connected to aluminum, etc. Another is a parallel setup, where the same metals are connected to each other. The more cells in a series setup increases the voltage while the more cells in a parallel setup increases the current.

Hypothesis


My hypothesis is that acidity and the salt used will affect the efficiency of the battery. I hypothesize that some salts will work better than sodium chloride, increasing voltage. I also hypothesize that the more acidic the liquid medium used is, the more voltage there is too.

Materials

10% salt solution (20g salt in 200 mL of water)
15% salt solution (30g salt in 200 mL of water)
Various probes
Salts (Magnesium sulfate, potassium sulfate, ferric sulfate, potassium nitrate, ammonium chloride, sodium nitrate, copper (2) sulfate pentahydrate, zinc chloride)
Apple Juice
Copper and Aluminum sheets
Paper towels

Procedure


It was a simple procedure. I tested various salt solutions for each battery. I measured voltage only as I only expected to voltage to change. I created cells in cups like the previous battery experiment and connected them using alligator clips. I tested different concentrations of the solution to see if the outcome. I kept a salt water battery to the side to compare the results.

Due to unwise use of time, I was only able to test one liquid more acidic than water. That was apple juice. However, after discovering a voltaic pile was a much more efficient way to create a large battery in a short period of time, I decided to use that as my test subject. First I created a 3 cell battery with salt-water soaked paper towels wedged between each metal sheet in each cell. I then measured the voltage which turned out to be about 1.65. I then used apple juice-salt solution to soak the paper towels. The results were showed that using apple juice increased the voltage a little, to 1.95. Although I conducted only one test, I hypothesize that acidity does affect the battery's efficiency.

All results are from a single cell.
Solution Used
10% Solution Voltage
15% Solution Voltage
10% Solution Current
15% Solution Current
Sodium Chloride




Potassium Sulfate




Ferric Sulfate




Potassium Nitrate




Ammonium Chloride




Sodium Nitrate




Copper (II) Sulfate Pentahydrate




Zinc Cloride




Magnesium Sulfate